Before posting any mechanic to the Mechanic Encyclopedia for ALL, by @ChargingBadger
, I would recommend you read this tutorial. Here I shall list all the features of what I think makes a good mechanic, and how you can make your not-so good mechanic into a good mechanic.
In case anyone doesn't know, I am VERY skeptical of most custom mechanics.Criteria for a Good Mechanic:1. Originality.
This is, debatably, the most important thing while making a good mechanic, and making original mechanics also happens to be the hardest of all the steps.. If your mechanic is too similar to an already made one, players won't like it, and it's clear that the cards you make with it won't be very original; after all, why not just use the already made one.2. Playability.
Your mechanic should be good enough that you'll want to have it on a card, but not so good that cards with it have to cost absurd amounts of mana (this is my main problem with Annihilator). In order to get an idea of a mechanic's playability, make sure to ask cardsmiths around you for advice with this one! It's often very hard to determine if a card/ability is OP or UP, and an outside opinion can help.3. Good in draft.
These days, MTG is focused a lot on draft and, if a mechanic feels terrible to draft, it likely won't we well received. Think to yourself 'Would this mechanic be useful in sealed?' A mechanic that feels more like a sideboard mechanic, or only works in very specific situations can flop in a draft situation.
Imagine opening a pack with a card with your mechanic in it. Would you want to pick that card early, will it be useful in your deck, or would it be the last card going around, that all the players avoid?4. Narrowness.
How many card types can have this ability? Can it function on commons? Is it only good for specific situations or does it resort to being a mechanic for only one card?
This is a hard part to figure out for many fresh mechanic-creators. If what you're trying to do is too specific, if it can't be common or if it's too narrow in what it does, it probably won't be used.5. It is a downside mechanic?
This is really easy to tell. Just look at the ability and think 'Would I rather my creature have or not have this ability?'
There are exceptions to this rule, but generally don't make a downside mechanic, as people don't generally want to use them.